Vegetable Seed Calculator
Calculate exactly how many vegetable seeds to buy for any garden size. Enter row length or bed area and in-row spacing to get total seeds needed, seed packets required, thinning plan, and planting schedule by crop.
Vegetable Seed Calculator Tool
Why use this free vegetable seed calculator?
Built with the features most competitors miss — deeper inputs, benchmark data, and actionable guidance alongside the core calculation.
How to use this vegetable seed calculator
Seeds per 25-ft row (with 2x thinning)
| Vegetable | Spacing | Seeds for 25 ft row | Typical seeds/packet |
|---|---|---|---|
| Carrot | 2 inch | 300 seeds | 500 to 2,000 |
| Lettuce | 8 inch | 75 seeds | 300 to 1,000 |
| Bean (bush) | 4 inch | 150 seeds | 25 to 50 |
| Tomato (transplant) | 24 inch | 13 plants | 25 to 50 |
| Cucumber | 12 inch | 50 seeds | 25 to 50 |
| Pea | 2 inch | 300 seeds | 30 to 80 |
| Corn | 12 inch | 50 seeds | 25 to 100 |
How this calculator compares
LazyTools fills the gaps most competing tools leave open — deeper analysis, benchmark context, and actionable guidance alongside the core calculation.
| Feature | LazyTools | OmniCalculator | SeedsNow.com | Territorial Seed |
|---|---|---|---|---|
| 22 vegetable species | ✓ Yes | ✓ | ✗ | ✗ |
| Row and bed area modes | ✓ Yes | ✓ | ✗ | ✗ |
| Thinning factor option | ✓ Yes | ✓ | ✗ | ✗ |
| Seed packet estimate | ✓ Yes | ✓ | ✗ | ✗ |
| Spacing override | ✓ Yes | ✓ | ✗ | ✗ |
| Free, no registration | ✓ Yes | ✓ | ✓ | ✓ |
Vegetable Seed Calculator: Complete Guide
Calculating vegetable seeds before ordering prevents both shortfalls mid-planting and seed waste from massive over-ordering. This calculator gives accurate seed quantities for 22 common vegetables based on row length or bed area.
Seed quantity calculation method
For row-based planting: Seeds = (Row length in inches / Spacing in inches) x Thinning factor. For bed-based planting: Plants = Bed area (sq ft) / (Spacing in ft) squared; Seeds = Plants x Thinning factor. The thinning factor accounts for the common practice of planting extra seeds and removing excess seedlings to ensure a complete stand despite variable germination.
Understanding thinning
Thinning is standard practice for direct-sown vegetables, especially fine seeds like carrots, beets, and lettuce. Sowing 2x the needed seeds ensures that gaps from poor germination or early seedling loss are filled. The extra seedlings are removed (thinned) when they reach 1 to 2 inches tall, leaving one plant per spacing position. For transplants, no thinning is needed.
Seed packet sizes and planning
Seed packet contents vary enormously between species. Large-seeded crops (beans, peas, corn, squash, cucumbers) come in packets of 5 to 50 seeds, adequate for small gardens. Fine seeds (lettuce, carrot, beet, radish) come in packets of 300 to 2,000 seeds, far more than most home gardeners need for a single year. Buying half the packet for one season and storing the rest in a sealed bag in the refrigerator is a practical cost-saving strategy.
Succession sowing to extend harvest
Rather than sowing one large batch, succession sow 2 to 4 weeks apart to get continuous harvest. For a 30-ft carrot bed, sow three 10-ft rows spaced 3 weeks apart. This extends the harvest window from 2 to 3 weeks to 6 to 9 weeks for the same total area. Calculate seeds for each sowing block separately for accurate quantities.